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Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

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Re: Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

#41

Post by AnthonyMouse »

Dylan16807 wrote: post #39
AnthonyMouse wrote: post #34

Earlier quoted context omitted.

Wait, so does this imply (ignoring the time requirements) that you could do NP calculations with a feasible amount of energy , because the inputs and outputs are small? Combine that with something that uses time dilation to make it go fast (from our frame of reference) and you'd be giving even hypothetical quantum computers a silver medal.

If you're going to use time dilation so you can wait for the computer to calculate, it's hard to imagine a setup where the power needs of the computer are more than a rounding error in comparison.

If you're using time dilation the power needs of the computer (in terms of how much fuel you need) are proportional to the rate time passes inside. If the goal is to get the ratio way up there, the power consumption gets important.

Especially if you're using the velocity-based method and have to accelerate the fuel.

Re: Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

#42

Post by timschmidt »

est31 wrote: post #37

According to the paper, their demonstration chip MANA has 21k of JJ units, which according to their estimates correspond to around 5k transistors. To compare, a single Nvidia GA100 has 54 * 10^9 transistors.

Some versions of the venerable MOS Technologies 6502 have only 3,218 transistors. The Intel 8080 has somewhere between 4,500 and 6,000. 5k transistors is square in the middle of "plenty for a classic 8 bit micro". Enough to run a basic *nix or embedded RTOS.

Re: Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

#43

Post by Dylan16807 »

AnthonyMouse wrote: post #41
Dylan16807 wrote: post #39

Earlier quoted context omitted.

If you're going to use time dilation so you can wait for the computer to calculate, it's hard to imagine a setup where the power needs of the computer are more than a rounding error in comparison.

If you're using time dilation the power needs of the computer (in terms of how much fuel you need) are proportional to the rate time passes inside. If the goal is to get the ratio way up there, the power consumption gets important. Especially if you're using the velocity-based method and have to accelerate the fuel.

You'd be accelerating yourself, not the computer. If you launch the computer it just takes longer.

Re: Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

#44

Post by Strilanc »

AnthonyMouse wrote: post #34
philipswood wrote: post #25

Earlier quoted context omitted.

Energy is expended when you zero or set a bit. If you compute reversibly you need use special logic gates to not throw any bits away during the computation, like the Toffoli gate. All your operations need to have the same number of input and output bits and needs to be able to run forwards and backwards. Effectively you set or zero no bits during the entire computation that can't be losslessly reversed. If you struct…

Wait, so does this imply (ignoring the time requirements) that you could do NP calculations with a feasible amount of energy , because the inputs and outputs are small? Combine that with something that uses time dilation to make it go fast (from our frame of reference) and you'd be giving even hypothetical quantum computers a silver medal.

Not unless you can isolate the computer from environmental noise exponentially well. Otherwise you'll need to spend exponential energy on entropy removal / error correction (e.g. keeping the dilution fridge running).

Re: Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

#45

Post by bgnn »

oceanplexian wrote: post #31
philipswood wrote: post #25

Earlier quoted context omitted.

Energy is expended when you zero or set a bit. If you compute reversibly you need use special logic gates to not throw any bits away during the computation, like the Toffoli gate. All your operations need to have the same number of input and output bits and needs to be able to run forwards and backwards. Effectively you set or zero no bits during the entire computation that can't be losslessly reversed. If you struct…

My analogy probably isn’t perfect but isn’t this how an abacus or a slide rule works? You expend energy to set the values for computation but the act of computing and then reading them expends no energy.

Yeah this is a good analogy

Re: Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

#46

Post by bgnn »

Interesting. To give some context to the current problem: the classical (CMOS) logic gates energy is expended to charge or discharge the load capacitance of each electrical node during a state change. Charging a capacitor to a certain voltage requires E=CV^2 amount of (Joules) energy (C in Farads, V in volts). From this, half of it is the energy stored at the capacitor, other half is the energy converted to heat on the transistors. This is so far the most efficient way we can build large scale integrated logic, and at best it is 50% efficient. In reality there is also unwanted inefficiencies, making it close to 30% or so. Good to keep in mind: 100% of the energy becomes heat because the charged capacitor needs to be discharged at some point to change its state. This is becoming a huge thermal management nightmare.
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